Apparatus for detinning tin-scrap.



No. 888,410. PATENTEYD MAR. 31 1968.

M. LEITOH. APPARATUS FOR DETINNING TINfiCRAP.

APPLICATION FILED NOV. 30, 1906.

' 2 SHEETS-SHEET l I No 883,419. 'PATENTED MAR. 81, 1908.

M. LEITOH.

- APPARATUS FOR DE'TINNING TIN sGRAP.

APPLICATION FILED NOV. 30.1906.

2 SHEETS-SHEBT 2.

ff t

UNITED srnrns PATENT OFFICE.

MEREDITH LEITCH, OF ELIZABETH, NEW JERSEY, ASSIGNOR TO METAL PROCESS COMPANY,

A CORPORATION OF NEW YORK.

APPARATUS. FOR DETINNING TIN-SCRAP.

I Application filed November 30, 1966. Serial No. 345,815.

To all whom it may concern:

Be it known that I, MEREDITH LEITCH, a citizen of the United States, residing at Elizabeth, Union county, New Jersey, have invented certain new and useful Improve- 'rnents in Ap aratus for Detinning Tin- Scrap, of Whic the following is a full, clear, and exact description.

My invention relates to apparatus for de tinning tin scrap by the use of dry or anhydrous chlorin, and has for its object to avoid many of the difficulties which are .found tobe present in the use of chlorin gas for detinning, as now practiced.

The presence of air and other gases in the I det-inning chamber and in the tin scrap prevents or hinders the action of the dry chlorin by diluting it and by keeping itout of the folds and minute spaces in the tin scrap.

In carrying out my invention the tin scrap is submerged in liquid stannic chlorid introduced at the bottom of the chamber and entirely filling the chamber. This drives out all the gases from the chamber and the spaces in the tin scrap so that when the liquid is Withdrawn the dry chlorin will follow in after and come in contact with all the surfaces of the tin scrap in as p re and undiluted a state as it can be obtained.

The action of the undiluted chlorin on the tin isvery rapid and heatis generated. If undiluted chlorin is allowed to come suddenly in contact with a large body of the tin scrap, the temperature will rise to such a point as to vaporize the stannic chlorid (SnCF), causingthe vapor to mix with the chlorin and interfere with the process of det-inning and the recovery of the stan'nic chlorid.

In the process carried out by my apparatus the slow withdrawal of the stannic chloridfrom.the detinning chamber through an opening in the bottom gradually exposes the scrap above the liquid to chlorin and per- 'mits of so controlling the process that .too

great a rise in temperature is prevented. The result is that the scrap 1s more uniformly detinned and the stannic chlorid formed is prevented from vaporizing and interfering with the process.

VV hen stannic chloridis caused to flow through the tin scrap from above in combination with chlorin, the chlorin is greatly dissolved by the stannic chlorid and must be eliminated by a separating process, requiring Specification of Letters Patent.

Patented March 31,1903.

additionai apparatus for the elimination and I saving of the chlorin.

In the process carried out by my apparatus the stannic chlorid is brought intothe cham-j ber quietly from the bot-tom, in order to drive out the gases and is withdrawn in the'same way. The absorption of the chlorin is thereby practically avoided, as the sta'nnic chlorid presents only a level and undisturbed sursures and temperatures and isabsorbed by.

generated 1n the chamthe stannic chlorid ber.

In the process I provide a purifying chamber through which all the liquid product of the detinning chamber must pass. This chamber contains tin in veryfinely' divided 1 'form which reacts upon the hydrochloric acid converting it intostannic chlorid and hydrogen. The latter is allowed to esca e and not interfere with the chlorin in the e-v tinning chamber. In this purifying-cha n ber any dry chlorin dissolved in the stannicc chlorid is also acted upon and converted into stannic chlorid, so that the liquid product of the process will not contain free chlorin.

In detinning with dry chlorin, the stannic chlorid forms in globules on the tin scrap and obstructs the action of the chlorin on A the tin whenever the temperature of the I chamber is below the boiling point of stannic chlorid. Moreover, the gases generated in the process and not absorbed and any gases admitted along with the chlorin and not absorbed, interfere with the action of the chlorin by diluting it and later filling the chamber and stopping the inflow of chlorin and the detinning process.

chlorin supply is cut off whenever such con On the con trary in my apparatus and process, the

ditions arise and the detinning chamber is filled from the bottom with liquid starinic chlorid, which collects the globules of stan-' nic chlorid adhering to the scrap and drives U out the inert and interfering gases and on being withdrawn brings in a new supplyfof tion to completion' chlorin, so that the process is kept in opera;-

In detinning with dry chlorin below the boiling-polntof stannicchlorid, at thecom- .pletion of the process liquid stannic chlorid remains on the detinned steel as moisture and in ,lobulesand in the minute spaces, resulting in a loss of'the starrnic chlorid and a decrease in the value'of the steel and moreover is very disagreeable and harmful to persons wori 'ng the process when the cham- --ber is opened for renewing the-charge."

The process 7 rovides for collecting the. 'stannic chlorid y a final submersion of the detinned steel in stannic. chlorid, thus causing the globules to join in the general mass of liquid, and on withdrawing the liquid there is created a high degree ofvacuum to vaporiz'e' the stannic chlorid which remains as moisture and in the minute spaces. This vaporized stannic chloiid is thus condensed on the cool walls of the detinning chamber,

' resulting in a saving of the stannic chlorid them to remain one above and removal of it from the steel and making it less disagreeable and harmful to thewoikmen.;. 4

In handling stannic chlorid ithasheretofore been difficult to preventits coming in contact with the air and moisture. In my process I provide for handling. the stannic chlorid by pressure from above the stannic chlorid exerted by another liquid having no affinity, such as sulfuric acid (H This.

latter being also aflected by contact with the air and difiicult'to pump is covered by a thirdliquid which may be readily pumped and come in contact with the air, but which has no affinity for the, secondliquid For this third liquidI- use petroleum. The different specific gravities ares'uch .as to cause the other in the order name'd'and desired.

In detinn-ing with stannic chlorin it is difficult to obtain tight joints between parts of the apparatus separated from each other,

as, for instance, the cover of the detinning chamber.

It is also difficult to regulate the temperature of the detinning chamber. In my apparatus these difficulties are obviated by providing a seal which resists the'pressure when in use, being at that timein the formof a solid cement and is liquidwhen the parts are to be separated. With this seal I combine a coil through which steam or a cooling fluid can, be passed, as desired,.formelting or-solidifying the seal, as required,- and for controlling -.the temperature of the detinning chamber.

In order to avoid any disturbances when a vacuum is created above the stannic chlorid by mechanical means or by gravity causing the liquid to vaporize, Iprovide a cooling chamber which is located sufliciently below I the detinning chamber so that the liquid contained therein will not be drawn up when the vacuum is formed in the detinnin g chamber,

having meansto quickly reduce the temwater outlet controlled by the cock e.

lower-end of this coil-is connected with an.

Figure 1 represents the apparatus, Fig. 2

represents a modification of the means for controlling the stannic chlorid.

Referring more particularly to the draw.-,.

ings, A represents the detinning chamber imit'the perforated removable having wit basket B containing tinfscrap This chamber. has a double walhfrming a space surroundingthe. chamber," within which is. a

quantity of paraflin C, and-also a coil-D the upper 'end of which E is connectedwith a" steam inlet controlled-by the cock e, and a The outlet for condensed-steamcontrolled by the cock e? and with an'inlet for cold water controlled by the cook 2 When steam is ad' mitted to the coil D the that the cover A with in lace and cold water is passed through the coil D, the paraiiin is hardened so as to seal the cover with a solid cement, making an air andg'as tight joint. The passage of the cold water through the coil D also reducesthe paraflin is melted soits depending flangecan be easily removed. When the cover is temperature of the space within the chamber A. Apipe F enters the chamber from below .and has at its u per [end a terminal F enter the cap A 0 the cover A. This terminal is connected with the portion F by a swivel joint 'F so that it can be turned to one side inorder to permit the removal and insertion of the basket B. A gagehaving-a glass portion G has one end connected to the pipe F and the other end connected to the bottom of the chamberA so as to indicate the height of the liquid within the chamber. The pipe F is branched, one branch leading to arn-air inlet H havingan inwardly opening check valve H, and a,-c'0'ck H and the other branchleading to an inlet I for admitting dry chlorin having an inwardly opening check valve I and a stop cock I From the bottom of the detinning chamber leads a pipeJ,'which has a valve K and is connected to a vent'pipe'Lhaving an outv wardly opening check valve L and 'a' stop cock L A second detinning chamberA". .i

similar to the detinning chambenA is connected to the inlets Hand I and the vent' L by corresponding passages-F and J 9. A third detinning chamberA is also connected to the inlets H and I and the vent L by pipes F and J corresponding to'the pipes F and J, and having corresponding stop cocks. The

pipes J, J and J are conrfec'ted by branches M, M and M to a purifying chamber N,

I rid as desired. The pipe Q is provided with the (ion which is surrounded by a water jacket 0,

through which cold water continually passes.

The cover of this purifying chamberv 18 connected with a vent pipe 1 having an outwardly opening check valve P. The pipes M, M M are provided with stop'cocks m, 'm f-m The purifying chamber is filled with pure tinN in some finely divided form. A V pe Q- asses through the bottom of the puriymg c amber N nearly to the top thereof, andis provided with a stop cock Q. This pipe leads to a holder R which contains a sufci'ent amount of anhydrous stannic chlorid to slightly more than fill the detinning chamber A. This holder is provided with a drawofi cock R for drawing ofi the stannic chloa second stop cock Q around which is a bypass containing a pump S. This by-pass has stop cocks S .8 so that the pump can be cut out when the sto cock Q is open, and the stop cock Q close when the passage through pump is open. The holder R has a b e wall containing a liquid seal R into which. dips the flange of the counterweighted cover R The space within the cover above stannic chlorid is filled with an inert gas such "within a draw-off cock Y.

as dry air. is connected with the holder R, the ower end of the gage being connected to the bottom of the holder Rand the u r end being-connected d'th the pipe w ch extends above the stannic chlorid within the holder.

,In'Fig. 2 a modified form of the holder and means for handling the stannic chlorid is provided. In this form the pipe g corresponding to the pi e Q-in Fig. 1 is connected di-- rectly to the ottom of a holder Y provided This holder is of such size as to contain sufficient stannic chlorid to fill the chamber A, the stannic chlorid when the chamber A is empty rising 'to the point Y and also a slightly greater amount of some liquid-of smaller specific gravity than stannic chlorid, and which will not combine therewith, such, for instance, as sulfuric acid, and also a layer of a still lighter fluid which will not combine with the sulfuric acid, such as et-roleum.- A gage having a glass portion has its lower end connected with the lower part'of the me Q and its upper portion opening into the older air vent X.

Y above the lower line of the petroleum. The gage has within it divisions of petroleum, sulfuric acid and stannic chlorid which correspond in height to the divisions in the holder Y. ,From the upper end of the holder Y leads a pipe W', which is connected to the bottom of a second holder X having an The pipe W has two by-passes, one of which contains a stop cock WQwhile the other contains stop cocks W W? and a A gage having a glass ortion T A through valve L to the-went;

anhydrous stannic chlorid to -fillv the detinning chamber A, and the valves that would expose the tin chlorid to the action of the atmosphere must be closed. The cover over the detinning chamber is st removed, the paraffin seal 0 being first melted by the ad mission of steam to the steam coil D. The perforated metal basket B filled with tin scrap is then placed in the detinning chamber A. I .The tin scrap should-be dry. The cover is now replaced and the paraffin seal. hardened by admitting cold water: through the coil D instead of -steam.- The detmnin chamber A is filled with tin scrap and sealed from theatmosphere. A communication through the system. of ipes from chamber A to chamber A is me e by opening valves H H in'the piping connections from the top of chamber A toward the to of chamber A and the valves K and L rom the bottom of chamber A to the vent L. The jstannic chlorid allowed to quietly descend to the holder. Chlorin gas. will now flow through the check valve I andthe valve I into chamher A at constant pressure andfill the s' ace above the descendin stannic chlorid am act on the tin scrap. en all of the chlorid has descended and been withdrawn from the chamber, the chlorin will continue to flow in ,1 at constant pressure anddetin the tin scrap, converting it into stannic chloriduntil the inert gases unavoidably contained in the chlorin fill the chamber and prevent further entry of chlorin. During this process of-ab- 1 sorbing the chlorin, cold water is kept in circulation through the coil D so as to absorb the heat of chemical action and control the tern erature of the chamber; keeping it below roiling point of stannic chlorid. At the 1 same time the chlorid is condensed on the tin scra and on the cool walls of the chainber an runs down through. the purifying chamber N into the holder. The presence of the purifying chamber results in alwa s 1 maintaining the tin chlorid within the hol er free from dissolved chlorin and converts the hydrochloric acid (HOD formed in the chain-- her into stannic chlorid. When the chlorin has ceased to flow into the chamberA, orzthe i flow is very slow, the valve Pin the chlorin inlet is closed andvalve H opened, thus cstablishing. again conimunicationfrom chamher A with chamber A and from chamber Stannic- 1 chlorin is now again pumped u into the chamber A and the inert gases 'vcn through chamber A? to the vent The tin scrap being new submerged in stannic .chio

r d. the globules. of which 1-30 carried, down into the holder R, when the 4 fstannic chlorid is withdrawn.

- tinning.

chamber and expel the gases.

The valve 11 is now again closed and I opened and the stannic chlorid again allowed to return to the holder and the chlorin to again flow into the chamber to complete the operation of de- This operation is to be repeated as often as found necessary by observation to completely remove the tin from the tin scra When the detinning is completed the valve is closed and valve H opened and the gaseous contents of chamber A driven out to the vent through chamber A by the stannic 'chlorid as previously described, the chlorin mixed with the gases driven out being absorbed by the tin on the tin scrap in chamber A. The valve H is now closed and the stannic chlorid in chamber A allowed to return to the holder, which being situated a sufficient distance below the chamber A will act to create withinthat chamber a high degree of vacuum and the stannie chlorid remaining on the d'etinned scrap at the time of withdrawing the stannic chlorid (the chamber and contents having been ke t at proper temperature) will be vaporizer by the heat in itself and the heat in the detinned scrap mass and condensed 011 the walls of the chamber cooled by the circulation of water through the coolin coil. At the same time the stan nic chlori in the purifier must be sufiiciently cooled to prevent evaporation which would otherwise occur on account of the lowered pressure. When the condensed stannic chlorid has drained out of chamber A the valve K immediately below it is closed and valve H opened and air admitted through pipe H from blower H to break the vacuum in the The air is preferably heated. The cooling water is now .shut 0H from the coil D and steam turned in to it to melt the paraflin in the seal, the cover ing new tin scrap placed'in the chamber. During the time that the stannic chlorid in chamber A. is being condensed, the cover removed and thedetinned scrap removed, new tin scrap is put into chamber A and the cover replaced and sealed. The operation of detinning is now carried on in chambefA? venting into chamber A the same as (le scribed for the operation of chamber A to chamber A, when connected with chamber Chamber A is also used in connection with chamber Ain the same way. From time to time the accumulation'of tin'chlorid in theholder is drawn oft.

The arrangement of Fig -2 is for the purpose of avoiding passing the stannic chlorid through a pump which is attended with some difficulties. In this apparatus the holder has a pipe connection from its lowest point to the purifier and a pipe connection from its highest point to the pump with a by-pass aroundthe pump to the lowest point of another vessel open to the'atmosphere at its highest point. Petroleum and another liquid as H 80 which is not affected by stannic chlorid fills the space in the holder above the stannic chlorid; also there is sufiicient petroleum in the other vessel to equal the contents of one of the detinning chambers. The stannic chlorid is caused to rise through the pipe A and the purifier filling the detinning chamber by pumpingpetroleum into the holder above the H SO and 81101 and forcing theformer downward and the SnCl; out at the bottom and up into the detinning chambers.

The chambers and pipes etc. are preferably made of iron since it is but little at-- tacked by the gases and liquids present.

The process described but not claimed herein is claimed in a co-pendin'g application filed as a division of this application.

What I claim is:

1. In an apparatus for detinning tin scrap, the combination of a detinning chamber, a holder for stannic chlorid, means for supplying an anhydrous chlorin gas to the detinning, chamber, and means for transferring the stannio chlorid to the detinning chamber and withdrawing it from. the detinning chamber to the holder so as to expel and. draw in gases into said detinning chamber, and valves for controlling the course and source of said gases.

2. In an apparatusfor detinning tin scrap, the combination of a detinning chamber, a holder for stannic chlorid, means for supplying an anhydrous chlorin gas to the detinning chamber, and means for transferring the 105 stannic chlorid to the detinning chamber and withdrawing it from the detinning chamber to the holder so as to expel from and draw in to-said detinning chamber gases, and valves for controlling the course and source of said 110 gases and the time when the gases shall be admitted.

3, In an apparatus for detinning tin scrap the combination of a detinning chamber, a

holderfor stannic chlorid, means for supply to the holder, and means for causing a vaouv um to be formed upon the withdrawal of said stanmc chlorid.

4. In a detmning chamber, the comblna- .tion of a wall having a recess therein, a removable cover having a depending flange adapted to fit within said recess, a seal in said recess consisting of an inert material which changes into liquid. form upon a rise or temperature; and means witl'iin, said recess for varying the temperature of said seal.

acacia.

5. In a detinning apparatus, the combina tion of a detinn'ing chamber, sources of heat in and cooling mediums, and means for circu ating said heating and cooling mediums about said chamber at dlflerent times, and means ior supplying chlorin gas to sald chamber.

6. In a' detinning apparatus, the combina tion of a detinning chamber, a holder for stannic chlorid, means for causing said stan nic chlorld to enter said detmnmg chamber and expel inert gases therefrom, to withdraw from said chamber and draw in to the same dry chlorin gas.

7. In a detinning apparatus, the combina tion of a detinning' chamber, a holder for chamber, and means for contro stannic chlorid, a pipe leading from said holder to the bottom of said chamber, means for causing the stannic chlorid to flow from the holder to. the chamber, a gas inlet and outlet opening in the upper part of said ing said gas inlet and outlet. v

8. In a detinning ap ara'tus, the combination of a detinning chamber, a holder for fstannic chlorid, a connection between the bottom of said chamber and said holder, means for causing the st-annicchlorid to. flow to and fro between said holder and said. chamber, and a purifying chamber located between said holder and said detinning chamber.

9'. In a detinning apparatus, the combiner tion of a detinning c amber, a holder for stannic chlorid, a connection between the bottom of Saidchainber and said holder, means for causing the stannic chlorid to flow to and fro between said holder and said chamber, and an auxiliary chamber located between said holder and said detinning chamber and means for cooling said auXil-- iary chamber.

chlorid, a connection between said detinning chamber and said holder, and means for causing said relatively inert liquidto exert a pressure upon said stannic chlorid suificient to cause it to displace and flow into said chamber.

12. In adetinning ap aratus, the combination of a detinning c amber, means for supplyingchlorin gas thereto, a holder for stamiic chlorid, means for causing the stannic chlol'id to flow at different times from said holder to said chamber and from said chamber to said holder, and means for controllin the temperature of said chamber independently of the fluids within said chamher.

I MEREDITH LEITCH.

Witnesses:

H. B. BR pWNELL, L. VREELAND. 

